Art of forming tubes



W. N. VANCE.

ART OF FORMING TUBES. APPLICATION FILED JUNE 12. 1915.

' 1,344,105. Pa'wnted June 22,1920.

UNITED STATES WALTER N, VANCE, OF CHICAGO HEIGHTS, ILLINdIS, ASSIGNOR TO DURAND S TEEL PATENT OFFICE- LOCKER COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

ART OF FORMING TUBES.

Application filed Ji'une 12, 1915. Serial No. 33,674.

To all whom it may concern:

Be it known that I WALTER N. VANCE, a

I citizen of the United states, residin in Chiing tubes and has more particular reference to the provision of tubes of polygonal or partial polygonal cross section.

Prior to my invention considerable difii culty has been experienced in the provision of tubes provided with slots, perforations and the like, which are made in the stock before the tube is formed. Tubes in accordance with the usual practice are drawn through rolls, which operation destroys the accuracy of any apertures or slots that may have been formed in the stock from which the tube is formed. If the tubes are made over mandrels the operation becomes expensive and-requires cumbersome machinery.

It is a principal object of this invention to provide for the economical manufacture of tubes having accurate perforations or slots without danger of distorting such perforations or slots in the forming of the tube and without the provision of complicated and diflicultly operated machinery.

Other objects and advantages of'the invention will be apparent as it is better understood from the following description when considered in connection with the accompanying drawing illustrating a preferred embodiment thereof.-

Figure 1 is a sectional view through dies provided for the initial bending of the tube of the character shown on the draw- Fig. 2 shows the same after its' first operation;

Fig. 3 after the next operation;

,Figs. 4 and 5 are views of a second set of dies used in forming a tube in accordance with my invention;

Fig. 6 is aview of the mechanism for performing the final stage in the forming of the tube; and

This invention relates to the art of form-' Specification of Letters'ratent. Patented J ine 22,1920.

cross section having close'dedges 9,.although it will be manifest that other forms of tubesmay be made in accordance withmy invention without departing from its spirit and sco e. 1 a

n accordance with m invention it is intended to form the full ength tube through a succession of steps, each step acting throughout the length of the tube and with equal force on all parts of it. This eliminates any drawing or tendency to distort the 1 metal forming the tube which would destroy the accuracy of any apertures or slots pro-' vided in the stock. The stock is subjected to pure bending forces without being placed under tension which would damage it. It

will .be noted as the invention is better understood that certain parts of the tube are not operated upon at all in its formation. The tube is first bent to provide the desired corners, theedges which are to abut being maintained in spaced relation through the deflection of a side of the tube as indicated generally in Fig. 5. Thereafter this deflection is eliminated to bring the edges to gether where they may be welded or otherwise secured together or left in mere abutment as,desired.

For the purpose of illustrating this invention I have shown on the drawings two sets of dies 10, 11 and 12, 13. In the tube shown on the drawing it is desired to have contacting outwardly extending edges 9 and to this end these edges are formed in the dies 10, 11, although they are by no means necessary to the invention; iewing Fig. 1 it will be noted that the male die 10 is provided with two deflecting points 14 and the female die 11 with correspondingly shaped pockets 15. A sheet 16 of suitable width is placed between these dies with its edge 17 extending beyond the center of the female die a distance equal to the desired width of an edge 9. At the center of the die a hardened edge 19 may be positioned if desired. \Vhen the die 10 descends the stock. of the sheet is bent, as seen in Fig. 2, forming an edge part 9 and a half of one side wall 21 of the finished tube. The other edge is similarly treated, as seen in Fig. 3. This may be accomplished by inserting from the other side of the die or by mere turning end for end. The stock of the tube is then in the form shown in Fig. 4 and in this position is placed between the dies 12 and 13.

These dies bend the stock into the form shown in Fig. 5 and to this. end the die 13 has inclined side walls 22 and a bottom wall 23 which is higher at its center than at the sides. This bottom wall is defined by two surfaces 24 disposed at right angles with the surfaces 22. The die 12 is faced in accordance with the bottom, being higher at its 1 center 25 than at its edges 26 so that when the die descends the two longitudinal corners 27 are formed. This completes the formation of the tube corners, the other two corners 28 having been formed in the dies 10, 11. In fact this operation completes the formation of the tube except for the elimination of the deflection 29. This deflection holds apart the edges 9 of the stock and per mits the withdrawal of the die 12. AL. though in the present instance this die is materially larger than the spaced distance between the edges 9 the flexibility of the material will permit it to be removed. The partly formed tube is then placed upon a smooth flat or slightly concaved support 31 and a pressure member 32 inserted between the edges 9 and moved downwardly to remove the deflection, bringing the edges 9 in close contact with the pressure member 32. The deflection is completely removed and the edges prevented from closing b pressure of the pressure member. 9 pward movement of the pressure member produces a removal of the pressure member from the tube through engagement with stripping members 33 which cause the tube to slide off the edge of the pressure member and the edges 9 to snap together. Thereafter the edges may be welded or otherwise secured as may be desired. If desired the stock may be bent in the manner described to slightly space the outward oflsets or edges 9 in order that a partition may be inserted between them when the tubing is used for metal shelving.

The tubes or posts may be provided with perforations 34: adapted to receive fastening members for cross-shelves or for other urposes and these perforations may be ma e in the stock in the flat,the pure bending action to which it is later subjected having no tendency to draw the material and destroy the accuracy of the perforations;

It is thoughtthat the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing any of its material advanta es, the form hereinbefore described being merely a preferred embodiment thereof.

I claim 2- l. The process of making closed sheet metal tubes of rectangular cross section, which consists in forming all the longitudinal edges and deflecting one of the side walls to maintain the edges in separated relation, and subsequently returning said deflected wall to flat condition by the insertion ot a pressure member between said edges and withdrawin said pressure member in a re verse direction laterally outwardly through said edges.

' 2. The process of making closed sheet metal tubes of rectangular cross section, which, consists in forming all thelongitudinal edges and deflecting one of the side walls to maintain the edges in separated relation, and .subsequently returning said deflected wall to flat condition by the insertion of a pressure member between said edges and withdrawing said pressure member in a reverse direction laterally outwardly. through said edges, the dimensions of the tube parts being made such that they are brought into contact with the sides of the pressure member and come substantially into contact when the pressure member has been withdrawn.

3. The process of making closed sheet metal tubes of rectangular cross-section, which consists in forming all the longitudinal edges and deflecting one of the side walls to maintain the edges in separated relation, and subsequently returning said deflected wall to flat condition by insertion of ablade pressure member between the edges and withdrawing said pressure member in a reverse direction outwardly through said edges.

fl. A closed sheet metal tube of rectangular cross-section and formed by forming all of the longitudinal edges and deflecting one of the side walls to maintain the edges in separatedrelation, and subsequently returning said deflected wall to flat condition by the insertion of a ressure member between said edges and withdrawing said pressure member in a reverse direction laterally outwardly through said edges.

Signed in the presence of two subscribing witnesses.

WALTER N. VANCE.

Witnesses J. C. CARPENTER, J OI-IN W. MUNDAY. 

